/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/

/*
 *  Portable interface to the CPU cycle counter
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */

#include "tls/config.h"

#if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_PLATFORM_C)
#include "tls/platform.h"
#else
#include <stdio.h>
#define mbedtls_printf     printf
#endif

#if defined(MBEDTLS_TIMING_C)

#include "tls/timing.h"

#ifndef asm
#define asm __asm
#endif

#if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)

#include <windows.h>
#include <winbase.h>

struct _hr_time {
	LARGE_INTEGER start;
};

#else

#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <signal.h>
#include <time.h>

struct _hr_time {
	struct timeval start;
};

#endif							/* _WIN32 && !EFIX64 && !EFI32 */

#if !defined(HAVE_HARDCLOCK) && defined(MBEDTLS_HAVE_ASM) &&  \
(defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)

#define HAVE_HARDCLOCK

unsigned long mbedtls_timing_hardclock(void)
{
	unsigned long tsc;
	__asm rdtsc __asm mov[tsc], eax return (tsc);
}
#endif							/* !HAVE_HARDCLOCK && MBEDTLS_HAVE_ASM &&
								   ( _MSC_VER && _M_IX86 ) || __WATCOMC__ */

/* some versions of mingw-64 have 32-bit longs even on x84_64 */
#if !defined(HAVE_HARDCLOCK) && defined(MBEDTLS_HAVE_ASM) &&  \
defined(__GNUC__) && ( defined(__i386__) || (                       \
(defined(__amd64__) || defined(__x86_64__)) && __SIZEOF_LONG__ == 4))

#define HAVE_HARDCLOCK

unsigned long mbedtls_timing_hardclock(void)
{
	unsigned long lo, hi;
	asm volatile("rdtsc" : "=a"(lo), "=d"(hi));
	return (lo);
}
#endif							/* !HAVE_HARDCLOCK && MBEDTLS_HAVE_ASM &&
								   __GNUC__ && __i386__ */

#if !defined(HAVE_HARDCLOCK) && defined(MBEDTLS_HAVE_ASM) &&  \
defined(__GNUC__) && (defined(__amd64__) || defined(__x86_64__))

#define HAVE_HARDCLOCK

unsigned long mbedtls_timing_hardclock(void)
{
	unsigned long lo, hi;
	asm volatile("rdtsc" : "=a"(lo), "=d"(hi));
	return (lo | (hi << 32));
}
#endif							/* !HAVE_HARDCLOCK && MBEDTLS_HAVE_ASM &&
								   __GNUC__ && ( __amd64__ || __x86_64__ ) */

#if !defined(HAVE_HARDCLOCK) && defined(MBEDTLS_HAVE_ASM) &&  \
defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))

#define HAVE_HARDCLOCK

unsigned long mbedtls_timing_hardclock(void)
{
	unsigned long tbl, tbu0, tbu1;

	do {
		asm volatile("mftbu %0" : "=r"(tbu0));
		asm volatile("mftb  %0" : "=r"(tbl));
		asm volatile("mftbu %0" : "=r"(tbu1));
	} while (tbu0 != tbu1);

	return (tbl);
}
#endif							/* !HAVE_HARDCLOCK && MBEDTLS_HAVE_ASM &&
								   __GNUC__ && ( __powerpc__ || __ppc__ ) */

#if !defined(HAVE_HARDCLOCK) && defined(MBEDTLS_HAVE_ASM) &&  \
defined(__GNUC__) && defined(__sparc64__)

#if defined(__OpenBSD__)
#warning OpenBSD does not allow access to tick register using software version instead
#else
#define HAVE_HARDCLOCK

unsigned long mbedtls_timing_hardclock(void)
{
	unsigned long tick;
	asm volatile("rdpr %%tick, %0;" : "=&r"(tick));
	return (tick);
}
#endif							/* __OpenBSD__ */
#endif							/* !HAVE_HARDCLOCK && MBEDTLS_HAVE_ASM &&
								   __GNUC__ && __sparc64__ */

#if !defined(HAVE_HARDCLOCK) && defined(MBEDTLS_HAVE_ASM) &&  \
defined(__GNUC__) && defined(__sparc__) && !defined(__sparc64__)

#define HAVE_HARDCLOCK

unsigned long mbedtls_timing_hardclock(void)
{
	unsigned long tick;
	asm volatile(".byte 0x83, 0x41, 0x00, 0x00");
	asm volatile("mov   %%g1, %0" : "=r"(tick));
	return (tick);
}
#endif							/* !HAVE_HARDCLOCK && MBEDTLS_HAVE_ASM &&
								   __GNUC__ && __sparc__ && !__sparc64__ */

#if !defined(HAVE_HARDCLOCK) && defined(MBEDTLS_HAVE_ASM) &&      \
defined(__GNUC__) && defined(__alpha__)

#define HAVE_HARDCLOCK

unsigned long mbedtls_timing_hardclock(void)
{
	unsigned long cc;
	asm volatile("rpcc %0" : "=r"(cc));
	return (cc & 0xFFFFFFFF);
}
#endif							/* !HAVE_HARDCLOCK && MBEDTLS_HAVE_ASM &&
								   __GNUC__ && __alpha__ */

#if !defined(HAVE_HARDCLOCK) && defined(MBEDTLS_HAVE_ASM) &&      \
defined(__GNUC__) && defined(__ia64__)

#define HAVE_HARDCLOCK

unsigned long mbedtls_timing_hardclock(void)
{
	unsigned long itc;
	asm volatile("mov %0 = ar.itc" : "=r"(itc));
	return (itc);
}
#endif							/* !HAVE_HARDCLOCK && MBEDTLS_HAVE_ASM &&
								   __GNUC__ && __ia64__ */

#if !defined(HAVE_HARDCLOCK) && defined(_MSC_VER) && \
!defined(EFIX64) && !defined(EFI32)

#define HAVE_HARDCLOCK

unsigned long mbedtls_timing_hardclock(void)
{
	LARGE_INTEGER offset;

	QueryPerformanceCounter(&offset);

	return ((unsigned long)(offset.QuadPart));
}
#endif							/* !HAVE_HARDCLOCK && _MSC_VER && !EFIX64 && !EFI32 */

#if !defined(HAVE_HARDCLOCK)

#define HAVE_HARDCLOCK

static int hardclock_init = 0;
static struct timeval tv_init;

unsigned long mbedtls_timing_hardclock(void)
{
	struct timeval tv_cur;

	if (hardclock_init == 0) {
		gettimeofday(&tv_init, NULL);
		hardclock_init = 1;
	}

	gettimeofday(&tv_cur, NULL);
	return ((tv_cur.tv_sec - tv_init.tv_sec) * 1000000 + (tv_cur.tv_usec - tv_init.tv_usec));
}
#endif							/* !HAVE_HARDCLOCK */

volatile int mbedtls_timing_alarmed = 0;

#if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)

unsigned long mbedtls_timing_get_timer(struct mbedtls_timing_hr_time *val, int reset)
{
	unsigned long delta;
	LARGE_INTEGER offset, hfreq;
	struct _hr_time *t = (struct _hr_time *)val;

	QueryPerformanceCounter(&offset);
	QueryPerformanceFrequency(&hfreq);

	delta = (unsigned long)((1000 * (offset.QuadPart - t->start.QuadPart)) / hfreq.QuadPart);

	if (reset) {
		QueryPerformanceCounter(&t->start);
	}

	return (delta);
}

/* It's OK to use a global because alarm() is supposed to be global anyway */
static DWORD alarmMs;

static DWORD WINAPI TimerProc(LPVOID TimerContext)
{
	((void)TimerContext);
	Sleep(alarmMs);
	mbedtls_timing_alarmed = 1;
	return (TRUE);
}

void mbedtls_set_alarm(int seconds)
{
	DWORD ThreadId;

	mbedtls_timing_alarmed = 0;
	alarmMs = seconds * 1000;
	CloseHandle(CreateThread(NULL, 0, TimerProc, NULL, 0, &ThreadId));
}

#else							/* _WIN32 && !EFIX64 && !EFI32 */

unsigned long mbedtls_timing_get_timer(struct mbedtls_timing_hr_time *val, int reset)
{
	unsigned long delta;
	struct timeval offset;
	struct _hr_time *t = (struct _hr_time *)val;

	gettimeofday(&offset, NULL);

	if (reset) {
		t->start.tv_sec = offset.tv_sec;
		t->start.tv_usec = offset.tv_usec;
		return (0);
	}

	delta = (offset.tv_sec - t->start.tv_sec) * 1000 + (offset.tv_usec - t->start.tv_usec) / 1000;

	return (delta);
}

#ifdef MBEDTLS_NUTTX_PORT
static void sighandler(int signum)
{
	mbedtls_timing_alarmed = 1;
	signal(signum, sighandler);
}
#endif

void mbedtls_set_alarm(int seconds)
{
	mbedtls_timing_alarmed = 0;
#ifdef MBEDTLS_NUTTX_PORT
	signal(SIGALRM, sighandler);
	alarm(seconds);
#endif
}

#endif							/* _WIN32 && !EFIX64 && !EFI32 */

/*
 * Set delays to watch
 */
void mbedtls_timing_set_delay(void *data, uint32_t int_ms, uint32_t fin_ms)
{
	mbedtls_timing_delay_context *ctx = (mbedtls_timing_delay_context *) data;

	ctx->int_ms = int_ms;
	ctx->fin_ms = fin_ms;

	if (fin_ms != 0) {
		(void)mbedtls_timing_get_timer(&ctx->timer, 1);
	}
}

/*
 * Get number of delays expired
 */
int mbedtls_timing_get_delay(void *data)
{
	mbedtls_timing_delay_context *ctx = (mbedtls_timing_delay_context *) data;
	unsigned long elapsed_ms;

	if (ctx->fin_ms == 0) {
		return (-1);
	}

	elapsed_ms = mbedtls_timing_get_timer(&ctx->timer, 0);

	if (elapsed_ms >= ctx->fin_ms) {
		return (2);
	}

	if (elapsed_ms >= ctx->int_ms) {
		return (1);
	}

	return (0);
}

#if defined(MBEDTLS_SELF_TEST)

/*
 * Busy-waits for the given number of milliseconds.
 * Used for testing mbedtls_timing_hardclock.
 */
static void busy_msleep(unsigned long msec)
{
	struct mbedtls_timing_hr_time hires;
	unsigned long i = 0;		/* for busy-waiting */
	volatile unsigned long j;	/* to prevent optimisation */

	(void)mbedtls_timing_get_timer(&hires, 1);

	while (mbedtls_timing_get_timer(&hires, 0) < msec) {
		i++;
	}

	j = i;
	(void)j;
}

#define FAIL    do                      \
{                                       \
if (verbose != 0)                  \
mbedtls_printf("failed\n");   \
return (1);                        \
} while (0)

/*
 * Checkup routine
 *
 * Warning: this is work in progress, some tests may not be reliable enough
 * yet! False positives may happen.
 */
int mbedtls_timing_self_test(int verbose)
{
	unsigned long cycles, ratio;
	unsigned long millisecs, secs;
	int hardfail;
	struct mbedtls_timing_hr_time hires;
	uint32_t a, b;
	mbedtls_timing_delay_context ctx;

	if (verbose != 0) {
		mbedtls_printf("  TIMING tests note: will take some time!\n");
	}

	if (verbose != 0) {
		mbedtls_printf("  TIMING test #1 (set_alarm / get_timer): ");
	}

	for (secs = 1; secs <= 3; secs++) {
		(void)mbedtls_timing_get_timer(&hires, 1);

		mbedtls_set_alarm((int)secs);
		while (!mbedtls_timing_alarmed) ;

		millisecs = mbedtls_timing_get_timer(&hires, 0);

		/* For some reason on Windows it looks like alarm has an extra delay
		 * (maybe related to creating a new thread). Allow some room here. */
		if (millisecs < 800 * secs || millisecs > 1200 * secs + 300) {
			if (verbose != 0) {
				mbedtls_printf("failed\n");
			}

			return (1);
		}
	}

	if (verbose != 0) {
		mbedtls_printf("passed\n");
	}

	if (verbose != 0) {
		mbedtls_printf("  TIMING test #2 (set/get_delay        ): ");
	}

	for (a = 200; a <= 400; a += 200) {
		for (b = 200; b <= 400; b += 200) {
			mbedtls_timing_set_delay(&ctx, a, a + b);

			busy_msleep(a - a / 8);
			if (mbedtls_timing_get_delay(&ctx) != 0) {
				FAIL;
			}

			busy_msleep(a / 4);
			if (mbedtls_timing_get_delay(&ctx) != 1) {
				FAIL;
			}

			busy_msleep(b - a / 8 - b / 8);
			if (mbedtls_timing_get_delay(&ctx) != 1) {
				FAIL;
			}

			busy_msleep(b / 4);
			if (mbedtls_timing_get_delay(&ctx) != 2) {
				FAIL;
			}
		}
	}

	mbedtls_timing_set_delay(&ctx, 0, 0);
	busy_msleep(200);
	if (mbedtls_timing_get_delay(&ctx) != -1) {
		FAIL;
	}

	if (verbose != 0) {
		mbedtls_printf("passed\n");
	}

	if (verbose != 0) {
		mbedtls_printf("  TIMING test #3 (hardclock / get_timer): ");
	}

	/*
	 * Allow one failure for possible counter wrapping.
	 * On a 4Ghz 32-bit machine the cycle counter wraps about once per second;
	 * since the whole test is about 10ms, it shouldn't happen twice in a row.
	 */
	hardfail = 0;

hard_test:
	if (hardfail > 1) {
		if (verbose != 0) {
			mbedtls_printf("failed (ignored)\n");
		}

		goto hard_test_done;
	}

	/* Get a reference ratio cycles/ms */
	millisecs = 1;
	cycles = mbedtls_timing_hardclock();
	busy_msleep(millisecs);
	cycles = mbedtls_timing_hardclock() - cycles;
	ratio = cycles / millisecs;

	/* Check that the ratio is mostly constant */
	for (millisecs = 2; millisecs <= 4; millisecs++) {
		cycles = mbedtls_timing_hardclock();
		busy_msleep(millisecs);
		cycles = mbedtls_timing_hardclock() - cycles;

		/* Allow variation up to 20% */
		if (cycles / millisecs < ratio - ratio / 5 || cycles / millisecs > ratio + ratio / 5) {
			hardfail++;
			goto hard_test;
		}
	}

	if (verbose != 0) {
		mbedtls_printf("passed\n");
	}

hard_test_done:

	if (verbose != 0) {
		mbedtls_printf("\n");
	}

	return (0);
}

#endif							/* MBEDTLS_SELF_TEST */

#endif							/* MBEDTLS_TIMING_C */
